Energy conservation has become an important part of the environment. Manufacturing equipment
and maintaining it for peek performance is a priority. The Federal government has also established
guidelines for minimal efficiency ratings on equipment. Electric powered machines, for example,
air conditioning systems, used to rated with a C.O.P.(coefficient of performance), which
was a ratio of output divided by input. Useful to engineers, this factor did not give consumers
much to go on. To improve comparison shopping, a new rating EER (energy efficiency ratio)
was added to the specification tags on A/C units. This is a ratio of cooling capacity in
BTUs per hour divided by the electrical power in watts. Since this number could vary under
different climatic or room temperatures, a new rating, SEER (seasonal energy efficiency
rating) became the current guideline. This is an EER adjusted to be an average rating for
operation of the machine over a wide range of conditions.

Minimal ratings for residential central air conditioning system has been set at 10. Higher
efficiency units will use less electricity to run, but are more expensive to purchase. The
consumer must weigh the installation cost against the amount of use the system will get.
The new gas powered heat pumps are rated at a remarkable SEER of 27 or higher, and operate
similar to a co-generator (the heat produced by the engine that powers the compressor is
added to the heat pump circulation of refrigerant). All air conditioning and heat pump units
must have a SEER rating from the manufacturer. Window units, central systems, splits, rooftops,
etc., must carry a label with the information listed.

When a technician adjusts the air-to-fuel mixture on an oil or gas burning appliance (some
gas units are preset by the factory and cannot be adjusted), a comparison is made between
the heat of combustion and the heat of exhaust. The heat captured by the exchanger is its
efficiency. With the help of instruments and charts, conditions for clean combustion, such
as smoke and carbon monoxide or dioxide or oxygen output become part of the computation,
and an efficiency rating in percentage can be determined. This is done on site. The manufacturer
is required to test the appliance under a variety of conditions and give it a rating as
A.F.U.E. (annualized fuel utilization efficiency). Similar to the SEER rating, it gives
the consumer a guideline to use toward the purchase of the furnace or boiler. A label must
be attached to the machine listing this information.

The labels affixed at the factory listing the efficiency rating does not have to be permanent.
Improvements in equipment are being made constantly, and the labels may change more often
than the cabinets of the appliances.